The Bishop moves through the corners (diagonal) of hexagons, in a straight line. The Bishop moves in 6 directions across the chess board and remains on the same colour.
Note that the Bishop is able to move along the 3 diagonal grids. These are the hardest to spot at first. Notice how moves along the diagonal are NOT BLOCKED by any pieces not on the same diagonal grid.
With the Flatow Opening there are 2 Bishops each side, all on the same central diagonal grid.
With all the
other openings there are 3 Bishops each side, one on each diagonal grid.